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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
431

Characterizing Disaster Resilience Using Very High Resolution Time-Sequence Stereo Imagery

Julius, Alexandria Marie 19 December 2018 (has links)
No description available.
432

Spatial Distribution of Freshwater Mussels (Unionidae) in Ohio Brush Creek Watershed, Southern Ohio

Brown, Jason K. January 2010 (has links)
No description available.
433

Distributional Changes in Ohio's Breeding Birds and the Importance of Climate and Land Cover Change

Batdorf, Katharine E. 18 December 2012 (has links)
No description available.
434

[en] COMPARASION BETWEEN LAND USE AND LAND COVER DATA FROM TERRACLASS AND THE AGRICULTURAL CENSUS IN THE MUNICIPALITY OF LÁBREA - AM / [pt] COMPARAÇÃO ENTRE OS DADOS DE USO E COBERTURA DO SOLO DO TERRACLASS E O CENSO AGROPECUÁRIO NO MUNICÍPIO DE LÁBREA - AM

PRISCILA RIBEIRO DE CARVALHO DE MEDEIROS 06 March 2020 (has links)
[pt] Este trabalho propõe a comparação entre os dados do TerraClass 2004 e o Censo Agropecuário 2006 para analisar o uso de um na ausência do outro, para compreender o uso e cobertura do solo pela agropecuária na área de estudo. Através dos dados de uso e cobertura do solo do TerraClass 2004 e do Censo Agropecuário 2006, foi feita uma análise das áreas de cada classe que se enquadram como atividade agropecuária e uma comparação dessas áreas nas duas classificações. A análise utilizou o Sistema de Informação Geográfica (SIG) com imagens de satélite Landsat/TM 5 para auxiliar na análise visual qualitativa das classes e obter respostas sobre o uso e ocupação do solo no município de Lábrea. Foram escolhidos 16 setores censitários sobre os quais se tinha dados de classes referentes a agropecuária, analisando e percebendo uma variação percentual considerável em relação as duas classificações. A metodologia de comparação serviu para verificar que os métodos de aquisição dos dados do TerraClass 2004 e do Censo Agropecuário 2006 apresentam diferenças consideráveis nos resultados. Foram encontradas na classificação do TerraClass, através da análise qualitativa utilizando a imagem de satélite, dúvidas quanto a algumas classes sem vegetação, mas que não foram classificadas como atividade agropecuária, como desflorestamento, e essas consideradas duvidosas. Por fim, o presente trabalho conclui que não é adequado utilizar os dados do TerraClass na ausência do Censo Agropecuário, ou vice-versa, tendo em vista a disparidade encontrada em alguns dos setores censitários analisados. Sugere-se para trabalhos futuros um estudo específico para saber as causas das áreas desmatadas das classes consideradas duvidosas. / [en] This work proposes comparing data provided by 2004 s TerraClass and 2006 s Agribusiness Census, analyzing the validity of using one absent the other to comprehend the land cover in relation to said business within the studied area. The areas of the classes related to agribusiness were compared through the land cover reported in each classification. This analysis took place in a GIS environment with the use of Landsat/TM 5 to aid in the visual qualitative comparison of the data. The region of interest was the municipality of the Labrea district in the southern region of the Amazonas state. Sixteen census sector that showed agribusiness information were chose for the comparison of the percentages of area attributed to that business type. The variation of such areas was noteworthy and it was deemed that one should not use the two sources compared interchangeably as the information does not match. Moreover, some classes of the TerraClass classification stood out and regarded as uncertain – such as generic deflorestation and not forest – as, knowing the regions historical occupation and recent expansion of agribusiness, one would suspect that those are indeed related to the agents studied in this work.
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435

Addressing the urban heat island effect in Stockholm : An analysis of its presence and relation to land cover and urban planning / Urbana värmeöar i Stockholm : En analys av förekomsten och relationen till marktäcke och stadsutformning

Igergård, Fanny January 2021 (has links)
As urbanization and global warming increase, an increasing importance is set on that urban planning processes take the possible effects of urban heat islands into account. In order to provide local city planners with site specific knowledge of the current situation in Stockholm, this study has explored the intra-urban heat island effect in Stockholm municipality by identifying major problem areas as well as addressing the statistical relationship between temperature and factors relating to land cover and urban planning strategies. Remotely sensed land surface temperature (LST) and the Swedish National Land Cover Database (NMD) have formed the data basis for the analyses that were carried out using GIS. The LST and land cover information have been extracted from randomly placed circle polygons in order to create a sample for the statistical analyses.  The results show that there exist differences in temperature within Stockholm municipality, both within the municipality as a whole and between various urban characters. In both cases, land cover is identified as an important, but not sole, factor to explain the differences. On land areas, artificial non-vegetated surfaces and forest is identified as the land cover classes of most relevance when it comes to the urban heat island effect. For both land cover classes, a strong correlation to LST is seen. Even though certain uncertainties and limitations are embedded in the data as well as in the method choices, the study can conclude in that the urban heat island effect is present in Stockholm municipality and that it can be derived from both land cover and urban characters. / I takt med att urbaniseringen och den globala uppvärmningen ökar kommer högre krav ställas på att stadsplaneringen tar hänsyn till de effekter som väntas uppstå kopplat till urbana värmeöar. I syfte att bistå lokala stadsplanerare med platsspecifik kunskap om den nuvarande situationen i Stockholm har den här studien utforskat intraurbana temperaturvariationer i Stockholms stad genom att identifiera de mest utsatta områdena samt genom att undersöka det statistiska sambandet mellan temperatur och faktorer kopplat till marktäcke och stadsutformning. Markens yttemperatur uppmätt från satellit och Nationella marktäckedata (NMD) har utgjort det främsta dataunderlaget för analyserna som genomförts med hjälp av GIS. Genom att extrahera information om yttemperatur och marktäcke från slumpmässigt placerade cirkelpolygoner kunde ett urval till de statistiska analyserna skapas.  Resultaten från studien visar att det finns skillnader i temperatur inom Stockholms stad, både inom kommunen som helhet och mellan olika stadsbyggnadskaraktärer. I båda fallen kan marktäcke identifieras som en viktig, men inte ensam, faktor till att förklara skillnaderna. På landområdena identifieras exploaterad mark och skog som de marktäcken med störst betydelse när det kommer till urbana värmeöar. För båda marktäckena ses i studien en stark korrelation till yttemperatur. Trots att vissa osäkerheter och begräsningar kan kopplas till både använd data och de metoder som använts kan slutsatsen att effekten från urbana värmeöar finns i Stockholms kommun dras. Dessutom kan konstateras att effekten kan härledas både till marktäcke och stadsbyggnadskaraktär.
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436

Quantifying numerical weather and surface model sensitivity to land use and land cover changes

Lotfi, Hossein 09 August 2022 (has links)
Land surfaces have changed as a result of human and natural processes, such asdeforestation, urbanization, desertification and natural disasters like wildfires. Land use and landcover change impacts local and regional climates through various bio geophysical processes acrossmany time scales. More realistic representation of land surface parameters within the land surfacemodels are essential to for climate models to accurately simulate the effects of past, current andfuture land surface processes. In this study, we evaluated the sensitivity and accuracy of theWeather Research and Forecasting (WRF) model though the default MODIS land cover data andannually updated land cover data over southeast of United States. Findings of this study indicatedthat the land surface fluxes, and moisture simulations are more sensitive to the surfacecharacteristics over the southeast US. Consequently, we evaluated the WRF temperature andprecipitation simulations with more accurate observations of land surface parameters over thestudy area. We evaluate the model performance for the default and updated land cover simulationsagainst observational datasets. Results of the study showed that updating land cover resulted insubstantial variations in surface heat fluxes and moisture balances. Despite updated land use andland cover data provided more representative land surface characteristics, the WRF simulated 2- m temperature and precipitation did not improved due to use of updated land cover data. Further,we conducted machine learning experiments to post-process the Noah-MP land surface modelsimulations to determine if post processing the model outputs can improve the land surfaceparameters. The results indicate that the Noah-MP simulations using machine learning remarkablyimproved simulation accuracy and gradient boosting, and random forest model had smaller meanerror bias values and larger coefficient of determination over the majority of stations. Moreover,the findings of the current study showed that the accuracy of surface heat flux simulations byNoah-MP are influenced by land cover and vegetation type.
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437

Landscape dynamics from 1990--2010 and the human to apex predator (red-tailed hawk) relationship on La Gonave, Haiti

White, Justin Haehlen 21 January 2013 (has links)
The island of La Gonave, ~50 km northwest of Port-au-Prince, represents the subsistence Haitian lifestyle. Little is known about human--environment interactions on La Gonave. The first objective of this research was to investigate landscape dynamics through image classification, change detection, and landscape pattern analysis using Landsat 5 (TM) imagery from 1990--2010. Five land cover classes were considered: Agriculture, Forest/Dense Vegetation (DV), Shrub, Barren/Eroded, and Nonforested Wetlands. Overall image classification accuracy was 87%. The area percent change was -39.7, -22.7, 87.4, -7.0, 10.2%, for the respective classes. Landscape pattern analysis illustrated the encroachment of Shrub in core Forest/DV patches and the decline of Agricultural patch integrity. Agricultural abandonment, deforestation, and forest regrowth generated an increasingly fragmented landscape. The second objective of this research was to better understand the survival of the red-tailed hawk (RTH) on La Gonave by exploring the human--RTH relationship. We implemented a survey (n = 121) in 10 rural villages on La Gonave regarding their perceptions and interactions with the RTH during May--June, 2012. During fieldwork we sighted seven RTHs and found one nest. Many respondents noted the aggressive behavior of RTHs during nesting, suggesting reproductive behavior on the island. Our results indicate that RTHs inhabiting this island were not persecuted, despite intense predation of domestic chickens. Aside from predation near homes, villagers do not interact with the hawk as it remains out of sight. The RTH currently has no known predators, but it remains in danger of island extirpation due to ecological degradation. / Master of Science
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438

Lyme Disease and Forest Fragmentation in the Peridomestic Environment

Telionis, Pyrros A. 14 May 2020 (has links)
Over the last 20 years, Lyme disease has grown to become the most common vector-borne disease affecting Americans. Spread in the eastern U.S. primarily by the bite of Ixodes scapularis, the black-legged tick, the disease affects an estimated 329,000 Americans per year. Originally confined to New England, it has since spread across much of the east coast and has become endemic in Virginia. Since 2010 the state has averaged 1200 cases per year, with 200 annually in the New River Health District (NRHD), the location of our study. Efforts to geographically model Lyme disease primarily focus on landscape and climatic variables. The disease depends highly on the survival of the tick vector, and white-footed mouse, the primary reservoir. Both depend on the existence of forest-herbaceous edge-habitats, as well as warm summer temperatures, mild winter lows, and summer wetness. While many studies have investigated the effect of forest fragmentation on Lyme, none have made use of high-resolution land cover data to do so at the peridomestic level. To fill this knowledge gap, we made use of the Virginia Geographic Information Network’s 1-meter land cover dataset and identified forest-herbaceous edge-habitats for the NRHD. We then calculated the density of these edge-habitats at 100, 200 and 300-meter radii, representing the peridomestic environment. We also calculated the density of <2-hectare forest patches at the same distance thresholds. To avoid confounding from climatic variation, we also calculated mean summer temperatures, total summer rainfall, and number of consecutive days below freezing of the prior winters. Adding to these data, elevation, terrain shape index, slope, and aspect, and including lags on each of our climatic variables, we created environmental niche models of Lyme in the NRHD. We did so using both Boosted Regression Trees (BRT) and Maximum Entropy (MaxEnt) modeling, the two most common niche modeling algorithms in the field today. We found that Lyme is strongly associated with higher density of developed-herbaceous edges within 100-meters from the home. Forest patch density was also significant at both 100-meter and 300-meter levels. This supports the notion that the fine scale peridomestic environment is significant to Lyme outcomes, and must be considered even if one were to account for fragmentation at a wider scale, as well as variations in climate and terrain. / M.S. / Lyme disease is the most common vector-borne disease in the United States today. Infecting about 330,000 Americans per year, the disease continues to spread geographically. Originally found only in New England, the disease is now common in Virginia. The New River Health District, where we did our study, sees over 200 cases per year. Lyme disease is mostly spread by the bite of the black-legged tick. As such we can predict where Lyme cases might be found if we understand the environmental needs of these ticks. The ticks themselves depend on warm summer temperatures, mild winter lows, and summer wetness. But they are also affected by forest fragmentation which drives up the population of white-footed mice, the tick’s primary host. The mice are particularly fond of the interface between forests and open fields. These edge habitats provide food and cover for the mice, and in turn support a large population of ticks. Many existing studies have demonstrated this link, but all have done so across broad scales such as counties or census tracts. To our knowledge, no such studies have investigated forest fragmentation near the home of known Lyme cases. To fill this gap in our knowledge, we made use of high-resolution forest cover data to identify forest-field edge habitats and small isolated forest patches. We then calculated the total density of both within 100, 200 and 300 meters of the homes of known Lyme cases, and compared these to values from non-cases using statistical modeling. We also included winter and summer temperatures, rainfall, elevation, slope, aspect, and terrain shape. We found that a large amount of forest-field edges within 100 meters of a home increases the risk of Lyme disease to residents of that home. The same can be said for isolated forest patches. Even after accounting for all other variables, this effect was still significant. This information can be used by health departments to predict which neighborhoods may be most at risk for Lyme. They can then increase surveillance in those areas, warn local doctors, or send out educational materials.
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439

Studying land-use and land-cover change with high resolution data / an assessment of the Carpathian Ecoregion

Knorn, Jan 24 May 2012 (has links)
Naturschutzgebiete sind ein essentieller Bestandteil zur Wahrung natürlicher Lebensräume. Oft verfehlt die Einrichtung solcher Schutzzonen jedoch den erwarteten Effekt. Die größte Gefahr liegt hierbei neben dem Klimawandel im direkten Einfluss des Menschen. Besonders in Phasen sozioökonomischen Umschwungs und damit verbundenen Landnutzungsveränderungen oder auch illegaler Nutzung natürlicher Ressourcen, sind Naturschutzgebiete in ihrer Funktion gefährdet. Ziel dieser Arbeit ist somit, Ursachen des Landnutzungswandels sowie dessen Auswirkungen und Ausmaß am Beispiel des rumänischen Teils der Karpaten-Ökoregion abzuleiten. Das Untersuchungsgebiet ist ein wichtiges Zentrum für Biodiversität und in ihm befindet sich Osteuropas größte gemäßigte Waldregion sowie einige der letzten europäischen Urwälder. Rumänien umschließt mehr als die Hälfte der Karpaten und es ist hiernach von besonderem Interesse, Gründe und Auswirkungen des rezenten post-sozialistischen Landschaftswandels zu untersuchen. Mit Hilfe von Landsat Aufnahmen sowie einer ad hoc entwickelten Methode zur Klassifizierung großräumiger Gebiete, wurden Veränderungen in der Waldbedeckung für die post-sozialistische Zeit abgeleitet. Die Ergebnisse offenbaren großflächige Forstveränderungen, auch innerhalb von Naturschutzgebieten und Urwäldern. Institutionelle Umbrüche und eine rapide Umgestaltung in den Eigentumsverhältnissen, wurden als Hauptursachen herausgestellt. Rumänische Naturschutzgebiete erreichen nicht die gewünschte Effektivität und Urwäldern werden weiterhin dezimiert. Die Arbeit verdeutlicht den Einfluss sozioökonomischer Veränderungen auf die Entstehung von Raubbau und legt Defizite in der Effektivität von Schutzbemühungen zum Erhalt der Biodiversität und verbundener Ökosystemleistungen offen. / Protected areas are one cornerstone of conservation efforts to safeguard natural habitats from destruction and overexploitation. Still, many of these areas remain less effective than initially envisioned. Besides climate change, main threats originate from enduring human activities. Protected areas are particularly at risk during periods of rapid socio-economic changes, which can trigger widespread land-use change and illegal resource use. The main goal of this thesis is to assess the extend and underlying causes of land-use change in protected areas and forest habitats within the Carpathian Ecoregion. The Romanian Carpathians were selected as a focus area in this study, because they comprise Eastern Europe’s largest continuous temperate forest region as well as some of the last and largest tracts of European old-growth forests, and they are a major hotspot of biodiversity. Romania comprises more than half of the Carpathian Ecoregion and it is of particular interest to study the causes and effects of land-use changes, which have emerged after the collapse of socialism in 1989. Post socialist forest cover change was quantified for the last 25 years using Landsat images and an ad hoc developed large area classification technique. Results show widespread forest disturbances, even inside protected areas and old-growth forests. Drivers of these disturbances can be related to institutional change and changes in ownership. The effectiveness of Romania’s protected area network in terms of its ability to safeguard biodiversity is most likely decreasing, and intact old-growth forests continue to disappear. This thesis reveals how rapid socio-economic changes may lead to overexploitation, and highlights substantial shortcomings in the effectiveness of protection efforts to safeguard biodiversity and related ecosystem services.
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440

Projecting land cover changes and impacts on bird conservation using geographic information system, remote sensing and a Cellular Automata – Artificial Neural Network model in Nairobi National Park, Kenya.

Ong'ondo, Frank Juma 13 December 2024 (has links) (PDF)
This study examines land cover changes and their projected future impacts on bird species conservation in and around Nairobi National Park, Kenya. 2016 and 2023 Satellite imagery, analyzed through Google Earth Engine and the MOLUSCE plugin were used to assess changes in five land cover types: grassland, shrubland, forest, urban, and water. Bird population data from the Kenya Bird Map were used to evaluate birds' responses to land cover changes. Birds were categorized into five habitat guilds—grassland-dependent, shrubland-dependent, forest-dependent, water-dependent, and urban-dependent bird species. Between 2016 and 2023, grassland and shrubland decreased by 14.21% and 5.54%, respectively, and urban increased by 19.85%. 2040 projection indicates declines in grassland (19.6%), shrubland (16%), and forest (5.64%), and increase in urbanization by 58.8% which reflect fluctuations in bird populations: grassland-dependent species declined by 27.5%, shrubland-dependent species declined by 6.3%, while forest-dependent, water-dependent, and urban-dependent species increased by 168%, 35.7%, and 101.5%.

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